Storm Prediction Center May-29-2004 1300 UTC Day 1 Convective Outlook www.nws.noaa.gov Site MapNewsOrganizationSearch Search SPC SPC Products All SPC Forecasts Current Watches Meso. Discussions Conv. Outlooks Fire Wx Forecasts Research Non-op. Products Forecast Tools Svr. Tstm. Events SPC Publications Weather Information Watch/Warning Map Storm Reports Current Radar Product Archive SPC FAQ Live SPC Weather Education & Outreach About the SPC About Tornadoes Cool Images Our History Public Affairs Misc. Staff What's New Links Contact Us SPC Feedback May-29-2004 1300 UTC Day 1 Convective Outlook Public Severe Weather Outlook The SPC is forecasting an outbreak of severe thunderstorms today and tonight across portions of the United States. This is an extremely dangerous situation. Please read the latest public statement about this event. Graphics: categorical| tornado| wind| hail Categorical Graphic Printer friendly version Probabilistic Graphics (more info) Tornado Damaging Wind Large Hail (Select thumbnails to view full images) SPC AC 291236 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0736 AM CDT SAT MAY 29 2004 VALID 291300Z - 301200Z THERE IS A HIGH RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 50 S RSL 25 SW RSL 30 N HLC 25 SSE BBW 30 ENE BUB 20 ESE OFK 20 SSW OMA 20 WNW STJ 40 ENE CNU 50 SW JLN 45 W MKO 35 SE OKC 35 N FSI 50 S RSL. THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM LTS 35 E GAG 50 SW RSL 25 WSW HLC 30 NNE MCK 25 N BUB 15 E HON 40 NNE ATY 35 WSW STC 30 NNE MKT 30 WSW MCW 10 SE DSM 45 NNE SZL 10 SSW SGF FSM 10 ENE DUA 20 ESE SPS LTS. THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 40 N CMX 45 SSW IMT 35 SSW RFD 55 NNW POF 45 NNW LIT 25 NW TYR 40 NW HDO 20 NNW DRT 45 ENE P07 55 S BGS 30 S CDS 15 S GAG DDC 35 NNW GCK 30 NE LAA 25 SSW LIC 45 WSW AKO 20 NE AIA 20 NNW PHP 30 SSW P24 80 NW MOT. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 SE P07 25 NNE BGS 10 SW CDS 40 NW GAG 35 WSW GCK 35 S LAA 10 E RTN 30 NNW SAF 30 WNW GUP 10 NNW GCN SGU 45 NE ELY 55 WSW MLD 15 WNW PIH 55 SW 27U 40 S S80 30 SSW LWS 10 SW GEG 45 NE GEG 65 NNW 3TH 40 SSE FCA 10 N BZN 25 SSW BIL 65 ENE BIL 35 NW MLS 60 NNW GGW ...CONT... 10 SE PLN 20 SW HTL 25 ENE GRR 35 SSE FDY 25 SSW MGW 35 SSW WAL ...CONT... 15 NNW DAB 50 NW AYS 45 SSW ANB 45 ENE GWO 35 SE TXK 30 SW TYR 40 NNW CLL 40 NW LRD. ...THERE IS A HIGH RISK OF SVR TSTMS FROM CNTRL OKLAHOMA TO SOUTHEAST NEBRASKA... ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK AREA FROM THE RED RIVER OF SRN OKLAHOMA TO SWRN MINNESOTA... ...THERE IS A SLGT RISK OF SVR TSTMS FROM SWRN TX TO THE NRN PLAINS/UPPER MISSISSIPPI VALLEY... ...SIGNIFICANT SEVERE WEATHER OUTBREAK LIKELY OVER PARTS OF THE SOUTHERN AND CENTRAL PLAINS THIS AFTERNOON AND TONIGHT... ...LARGE CITIES IN AND NEAR THE HIGH RISK AREA INCLUDE OMAHA AND LINCOLN, NEBRASKA...TOPEKA AND WICHITA, KANSAS...TULSA AND OKLAHOMA CITY, OKLAHOMA... ...A FEW STRONG, LONG-TRACK TORNADOES, LARGE DESTRUCTIVE HAIL, AND DAMAGING WINDS WILL BE POSSIBLE IN PARTS OF THE HIGH AND MDT RISK AREAS FROM THIS AFTERNOON INTO THE EVENING... MORNING WATER VAPOR SATELLITE IMAGERY SHOWS A STRONG AND PROGRESSIVE UPPER TROUGH OVER THE WEST WITH SEVERAL WELL-DEFINED SPEED MAXIMA ROTATING THROUGH THE LARGER SCALE TROUGH. A LEAD IMPULSE...NOW EMERGING FROM THE SRN HIGH PLAINS...WILL EJECT ENEWD ACROSS KS/OK/MO/AR OVER THE NEXT SEVERAL HOURS. A STRONGER UPSTREAM IMPULSE...NOW OVER THE LOWER CO RIVER VALLEY...WILL DRIVE THE MAIN UPPER TROUGH EAST ACROSS THE HIGH PLAINS LATER THIS AFTERNOON WITH LARGE 60-90M 12-HOUR HEIGHT FALL CENTER SPREADING ACROSS THE CNTRL AND NRN PLAINS THOUGH TONIGHT. IN RESPONSE TO THE LARGE SCALE DYNAMIC FORCING FOR ASCENT...A PRIMARY SURFACE LOW AND INVERTED TROUGH WILL MOVE ACROSS THE DAKOTAS THROUGH TODAY WHILE A SECONDARY LOW INTENSIFIES NEAR DRYLINE/COLD FRONT TRIPLE POINT ON THE NEB/KS BORDER. DRYLINE WILL BECOME ESTABLISHED SOUTH OF THE TRIPLE POINT LOW...FROM WCNTRL KS/SCNTRL NEB...INTO SWRN OK...AND ACROSS WEST TX. AS TRIPLE POINT LOW MOVES EAST THROUGH EVENING... A COLD FRONT WILL DEVELOP SOUTH ACROSS WRN KS AND THE DRYLINE WILL SURGE EAST ACROSS CNTRL KS/OK AND NCNTRL TX. ...SCNTRL NEB TO CNTRL OK... SCATTERED...MOSTLY NON-SEVERE...TSTMS SHOULD DEVELOP THIS MORNING AS LEAD IMPULSE MOVES ACROSS ERN OK AND INTO THE OZARKS. STRONG HEATING IN THE WAKE OF THIS LEAD IMPULSE WILL DEVELOP ALONG THE DRYLINE BY EARLY AFTERNOON RESULTING IN A VERY UNSTABLE WARM SECTOR WITH MLCAPE VALUES OF 3500-4000 J/KG. MODEST CONFLUENT LOW LEVEL FLOW COUPLED WITH LARGE SCALE HEIGHT FALLS ATOP THE DRY LINE WILL PROVE SUFFICIENT TO LOCALLY OVERCOME CAPPING INVERSION AND PROMPT POTENTIALLY EXPLOSIVE SUPERCELL DEVELOPMENT FROM SCNTRL NEB INTO SWRN OK. FORECAST SOUNDINGS SHOW STRONG LOW LEVEL SHEAR FAVORING TORNADOES. DIRECTIONAL AND SPEED SHEAR AND TORNADO POTENTIAL WILL FURTHER INCREASE FROM LATE AFTERNOON INTO THE EVENING AS SLY 850MB FLOW OF 40-45KT IS TOPPED BY WLY 500MB FLOW OF 50-60KT AND DRYLINE MIXES EWD INTO LOW LEVEL MOIST AXIS. PERPENDICULAR ORIENTATION OF THE DEEP LAYER SHEAR VECTOR TO THE DRYLINE...AND INITIALLY STRONG INHIBITION...WILL ACT TO MAINTAIN DISCRETE CELLS INTO THE EARLY EVENING FROM KS SOUTH TO THE RED RIVER. STRONGER INHIBITION WITH SWD EXTENT ALONG THE DRYLINE WOULD SUGGEST MORE ISOLD...BUT STILL POTENTIALLY SIGNIFICANT...ACTIVITY FROM CNTRL OK INTO TX. FROM CNTRL OK INTO SERN KS...AN AREA OF HIGHER LONG-TRACK TORNADO POTENTIAL MAY EXIST INVOF FAVORABLY ORIENTED DIFFERENTIAL HEATING/OUTFLOW BOUNDARIES LEFT IN THE WAKE OF MORNING CONVECTION AND CLOUD COVER. ANOTHER AREA FAVORABLE FOR MORE PERSISTENT SUPERCELLS AND TORNADOES WILL OBVIOUSLY BE NEAR THE TRIPLE POINT LOW ACROSS NRN/NERN KS. STRONG TORNADOES ARE LIKELY TO BE ASSOCIATED WITH THESE FEATURES DURING THE LATE AFTERNOON AND EVENING HOURS. LARGE DESTRUCTIVE HAIL AND DAMAGING DOWNDRAFTS WILL ALSO BE POSSIBLE WITH ANY SUPERCELL STORM. ETA RUN FROM 06Z AND 00Z 4KM WRF APPEAR TO SUGGEST A RELATIVE MINIMUM IN TSTM POTENTIAL FROM PARTS OF ERN KS INTO NWRN MO FROM LATE AFTERNOON INTO THE EVENING. IT IS NOT UNCOMMON FOR THESE TYPES OF OUTBREAKS TO EXHIBIT A BIMODAL PATTERN IN SIGNIFICANT SEVERE WEATHER WITH ONE CONCENTRATED AREA OF STORMS NEAR THE EXIT REGION OF MID/UPPER JET...AND THE SOUTHERN AREA NEAR THE ENTRANCE REGION OF THE JET. WHILE THIS SCENARIO MAY INDEED UNFOLD LATER TODAY...THERE IS INSUFFICIENT EVIDENCE TO SUPPORT DIVIDING THE HIGH RISK AREA INTO TWO AREAS AT THIS TIME. ...NERN NEB/ERN SD/IA AND MN... STRONGLY DIFFLUENT MID/UPPER LEVEL FLOW IS ALREADY SPREADING ACROSS THE CNTRL AND NRN PLAINS THIS MORNING WITH CONSIDERABLE CLOUD COVER NOTED ON SATELLITE IMAGERY OVER PARTS OF NEB AND THE DAKOTAS. HOWEVER...VERY STEEP MID LEVEL LAPSE RATES AND MODEST LOW LEVEL MOISTURE ACROSS THE REGION SHOULD RESULT IN INCREASING DESTABILIZATION IN THE WAKE OF MCS NOW MOVING ACROSS THE UPPER MS VALLEY. WHILE STRONG CAPPING/INHIBITION IS NOTED ON FCST SOUNDINGS ACROSS THE MO RIVER VALLEY THROUGH THE AFTERNOON...DIURNAL HEATING AND FORCING NEAR COLD FRONT OVER NWRN NEB...AND SURFACE LOW/WARM FRONT OVER ERN SD...WILL BE SUFFICIENT TO ERODE THE CAP AND PROMOTE VIGOROUS CONVECTIVE DEVELOPMENT IN THESE AREAS BY LATE AFTERNOON. CONVECTION WILL THEN DEVELOP EWD INTO GREATER INSTABILITY THROUGH THE EVENING. DEEP LAYER SHEAR ACROSS THE MIDDLE MO RIVER VALLEY IS FCST TO BE SOMEWHAT MARGINAL FOR SUPERCELLS GIVEN WEAK MID LEVEL FLOW WITHIN THE TROUGH AXIS. HOWEVER...ENHANCED SFC-1KM SHEAR NEAR THE SURFACE LOW AND WARM FRONT...IN ADDITION TO STRONG MESOSCALE FORCING AND ABUNDANT INSTABILITY...SHOULD FAVOR AT LEAST A COUPLE OF TORNADIC STORMS IN ADDITION TO A FEW VERY LARGE HAIL EVENTS. ACTIVITY IS LIKELY TO CONGEAL INTO ONE OR TWO LARGER CONVECTIVE SYSTEMS FROM WRN MN INTO NWRN IA DURING THE EVENING WITH AT LEAST A MARGINAL HAIL THREAT EXTENDING EWD ACROSS THE UPPER MS VALLEY INTO EARLY SUNDAY MORNING. ..CARBIN/TAYLOR.. 05/29/2004 ...NOTICE... FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3. THE INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED. NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED FOR 1630Z CURRENT UTC TIME: 1259Z, RELOAD THIS PAGE TO UPDATE THE TIME Top/Latest Day 2 Outlook/Today's Outlooks/Forecast Products/Home